Yarn twisting device



Ma h 1964 P K. NOORDENBOS YARN TWISTING DEVICE Filed Oct. 14, 1960 INVENTOR. PIETER KLAAS NOORDENBOS ATTOR NEY United States Patent 3,123,969 YARN TWISTING DEVICE Pieter Klaas Noordenbos, Ede, Netherlands, assignor t0 Algemene Kunstzijde Unie N .V., Arnhem, Netherlands, a corporation of Netherlands Filed Oct. 14, 1960, Ser. No. 62,648 Claims priority, application Netherlands Nov. 21, 1959 11 Claims. (Cl. 5777.45)

This invention relates generally to a device for imparting twist to yarn, and relates more specifically to a novel bearing arrangement for the spindle of a yarn twisting device capable of operating at high twisting speeds.

It is known to impart twist, particularly false twist, to thermoplastic yarn, such as yarn having a basis of a polyamide, by the use of a tubular twisting spindle. In such twisting devices, the thermoplastic yarn is curled by feeding the same from a suitable source of supply to a twist stop, through a heating means and a cooling Zone to the tubular spindle of a false -twisting device, from which the yarn is discharged, usually onto a suitable take up means. The spindle of such false twisting device is urged by means of a drive belt into the throat formed by one or more pairs of freely rotatable discs, each pair consisting of discs rotatably mounted about displaced axes. In this manner the false twisting spindle was floatingly mounted or radially positioned between the freely rotatable discs and the drive belt. Generally, means are provided for preventing movement of the spindle in an axial direction.

While many expedients have been proposed for preventing axial displacement of the spindle, among which were electromagnetic and permanent magnet means in the form of annular magnets fixed on the vertical spindle, a fairly satisfactory arrangement for this purpose is illustrated in Patent No. 2,855,750 to Schrenk et al. In the device of this patent the spindle is provided with one or more circular grooves or running surfaces and the rim of the rotatable disc reaches into the groove in the spindle to support the same for rotation and at the same time prevent axial displacement thereof. In this arrangement, in order to exclude the possibility of axial movement of the spindle, the rotatable discs and the grooves in the spindle together form axial bearings, thus effecting heavy wear on the rims of the rotatable discs. As the rims wear down, axial movement of the spindle Will occur with resultant detriment to the quality of the curl in the twisted yarn produced. Another disadvantage of this arrangement is that slip must necessarily occur between the rims of the rotatable discs and the circular grooves of the spindle, resulting in an inaccurate speed coupling between the rotatable discs and the spindle. This also gives rise to small speed fluctuations resulting in differences in the curling quality of the twisted yarn.

It is, accordingly, an important object of this invention to provide an improved bearing arrangement for preventing axial displacement of the twisting spindle of a false twisting device which will be free from the foregoing and other disadvantages and will be especially simple in construction and efiicient in use.

Another object of this invention is to provide a novel method and apparatus for supporting a spindle or a amass Patented Mar. 10, lgfil false twisting device whereby the spindle may be rotated at high speeds with substantially no wear to the spindle or driving discs.

Still another object of this invention is the provision of a bearing arrangement for a high speed false twisting spindle capable of movement from operative to incperative position while maintaining the spindle in driving relationship.

A further object of this invention is the provision of a novel bearing arrangement for the spindle of a false twisting device capable of positioning the spindle both radially and axially while supporting the same for rotation at high speed.

Other objects and advantages of this invention, together with certain details of construction and combinations of parts will appear from the following detailed description.

In accordance with this invention, the twisting spindle of the false twisting device is supported on one or more axial air hearings in such a manner that the cylindrical rims of the rotatable discs contact the cylindrical running surfaces of the spindle without applying any appreciable pressure thereon whereby there results substantially no wear on the rims of the discs or on the spindle. As the only contact between the rims of the discs and the spindle is by means of cylindrical surfaces, the speed coupling between the rims of the discs and the spindle is accurately determined by the ratio of the diameters of the discs and the spindle at their point of contact. Since the speed of the spindle may be accurately and uniformly maintained by the use of the air bearing of this invention, the curling of the twisted yarn is improved to a considerable degree, particularly the uniformity thereof.

In its broadest aspect, the bearing of this invention comprises an annular collar fixed to the top of the twisting spindle of a false twisting machine, the lower end of the spindle having a yarn encircling body for imparting a twist or curl to the yarn passing through the spindle. The collar forms an air bearing with an annular air chamber surrounding the spindle, the chamber having one or more upwardly directed apertures whereby air or other suitable gas under pressure from the chamber impinges on the lower surface of the collar on the spindle. This construction has many advantages. Thus, the spindle is readily assembled with the annular air chamber by slipping the same through the annulus of the air chamber from above. Furthermore, by passing the yarn vertically downward towards the yarn encircling body, the yarn tension and the weight of the spindle act in the same direction, making for stability in the position of the spindle. This arrangement is preferable where a ring twisting machine is used as a means for taking up the curled yarn.

The invention will be more readily understood by ref erence to the following detailed description, when taken in connection with the accompanying drawings in which:

FIGURE 1 is a perspective View of the preferred em bodiment of this invention,

FIGURE 2 is a detail view, mostly in section, of the twisting spindle, the air chamber and the rotatable discs, and

FIGURE 3 is a detail view, in cross-section and on an enlarged scale, of the air bearing arrangement in accordance with this invention.

Like reference numerals indicate like parts throughout the several views of the drawing.

Referring now to the drawings, there is shown a part of a frame 1 of an apparatus used for curling yarn, having a basis of a thermoplastic material such as a polyainide, according to the false twisting process. On frame 1 are normally mounted a series of false twisting devices generally indicated by reference numeral 2. However, only one false twisting device is shown in FIGURE 1, and only one will be described herein, it being understood that the other false twisting devices mounted on frame 1 will be identical to that shown in the drawing.

The false twisting device 2 comprises a tubular spindle 3 having a longitudinal passageway therethrough. To obtain optimum results it is desirable that the spindle have a uniformly cylindrical surface along substantially its entire length. At its upper end the spindle 3 has fixed thereon, as by shrinking, a collar 4. As shown, the collar may be in the form of a truncated cone. The lower end of the tubular spindle is provided with means for imparting twist or curl to the yarn travelling therethrough, said means comprising a diametrically extending bracket 5, a sapphire 6 carried thereby, and a groove 7 in the lower edge thereof.

An endless belt 8, only a portion of which is shown, which may be driven by any suitable means, not shown, imparts rotation to the tubular spindle 3 of the false twisting device 2. The belt 8 is urged into contact with the cylindrical surface of the spindle, between the collar 4 and the bracket 5, by a series of guide rollers 9, only one of which is partially shown in FIGURE 1. By virtue of the serpentine fashion in which the belt 8 passes alternately between the spindles 3 and the guide rollers 9, it exerts a continuous pressure against the spindle, urging the said spindle into the throat formed between the peripheral rims 10 of rotatable discs 11, and into contact with said rirns which are formed of wear-resistant rubber or other elastomer.

As is shown in FIGURES l and 2, two rotatable discs 11 are alfixed in spaced relationship to a shaft 12, two shafts being shown for the four rotatable discs shown. The shafts 12 are mounted for rotation in housings 13 in which are provided antifriction bearings of any conventional type, i.e. roller bearings, ball bearings, Teflon bearings, etc. The elastomeric rims 10, as will appear from FIGURE 2, consist of small discs of wear-resistant elastomer clamped between two metal plates 14 which have a smaller diameter than the elastomer discs whereby the rims 10 project beyond the peripheries of the metal plates. While it is preferred that the elastomer discs be vulcanized to the metal plates, any other suitable mode of attachment, such as by the use of adhesive, screws, etc., may also be employed.

The housings 13 are fixed in predetermined spaced relationship to an intermediate plate 15. This plate is mounted for swinging movement about a bolt 16 which extends through suitable apertures in plate 1 and in one end of plate 15, thus pivotally securing said plate to frame 1. A projection 17 extending from the free end of plate 15 cooperates with abutments 18 and 19 of positioning member 20 to limit the swinging movement of the plate 15 about its pivot point represented by bolt 16. The positioning member may be secured to frame 1 in any suitable manner such as by the screws shown in FIGURE 1. If desired, a separate latching means, not shown for it is well known in the art, for locking plate 15 in operative or inoperative position may be employed.

Heretofore, in order to prevent the spindle 3 from dropping out of position when intermediate plate 15 is moved counterclockwise, i.e. away from belt 8, a separate retaining mechanism was required. In accordance with the instant invention, however, the spindle is maintained in the desired vertical position by a mechanism including the air bearing. Thus, the said mechanism includes a column 21, longitudinally bored, fixed to intermediate plate 15, which carries at its upper end the air bearing, generally indicated by reference numeral 22, which will be described in detail below.

An aperture 23 is provided in the intermediate plate 15 to cooperate with an opening in frame 1, which opening is aligned with said aperture whether the false twisting device is in operative or inoperative position so that the yarn 24 may be guided in a vertical direction from a source of supply located above the false twisting device through the tubular spindle to a point below said spindle without damage to the yarn. A handle 25 is secured to the plate 15 to facilitate movement thereof between operative and inoperative positions.

Referring now to FIGURE 3 wherein the air bearing arrangement is shown on an enlarged scale, the air bearing 22 is shown as comprising an annular air chamber 25 provided with a nozzle 26 having a plurality of bores or openings 27 in the upper face thereof adapted to direct streams of compressed air onto the bottom surface of the collar 4. While the nozzle 26 is shown as a separate element, which may be of plastic material, if desired, pressed into position on the air chamber, it is to be understood the air chamber and the nozzle may be made as an integral unit.

The air chamber 25 may be connected to a suitable supply of compressed air or other gas, not shown, by means of a tube 28 connected to the bore of column 21 which in turn is connected to the supply of compressed air by any convenient means. The tube 28 is afiixed to the column 21 by a screw 29 in such a manner that it is possible by the turning of the screw to impart small variations in the positioning of the air bearing relative to the throats formed by rotatable discs 11, whereby accurate placement of the air hearing may be effected.

Although in the embodiment shown a single collar mounted at the top of the twisting spindle is employed, it is of course possible to mount a plurality of collars thereon with an air chamber under each collar arranged at least partially around the spindle. Furthermore, it is also possible to use a split collar, each portion of which rests on a separate air cushion formed by separate air chambers. However, said constructions have the disadvantage that they are assembled with greater difiiculty than where a single collar and an annular air chamber which completely surrounds the spindle is employed.

Where air chambers which do not completely surround the spindle are used, it is of course possible to slip the spindle with collars thereon into position over the air chambers. In this case there results an inefficient use of the compressed air as the air cushions on which the spindle collars rest are not wholly enclosed.

In devices for the false twisting of yarn it is known to use air bearings. However, in these false twisting devices the spindle forms part of a rotor of an electromotor, the rotor being rotatable about a vertical axis. As a result of the higher amount of mass inertia of the rotatable body of this type of false twisting device, the number of revolutions per minute which it is capable of making is far less than that made by the spindle of the false twisting device of the instant invention where the spindle has a relatively small amount of mass inertia.

Although in the embodiment shown the discs are fixed in pairs on freely rotatable shafts, it is also possible to arrange the discs each freely rotatable on fixed shafts or to arrange the discs in pairs on a hub which is freely rotatable around such a shaft.

The invention is also not limited to the mounting of the false twisting spindles of the type shown in the drawings. Other twist spindles, for example those in which the threads are passed around discs which are rotatable around the axis of the spindle or around an axis perpendicular thereto or spindles which do not have such discs, may be mounted in the manner indicated.

In the operation of the device of this invention, a

package with the yarn to be twisted is placed-on the bobbin holder above the device and the free end of yarn is passed between the pressure rollers, through the heater, as is Well-known in the art, and into the longitudinal passageway of twisting device 2, which device is locked in inoperative position for threading-in. The yarn thereupon is passed through said passageway and into the bore of sapphire 6, with one winding placed around the bracket 5. From the sapphire 6 the yarn passes to the discharge device and then onto a suitable take-up mechanism. As soon as the heater reaches the required temperature the entire device may be brought into motion and the spindle 3 may be shifted into contact with drive belt 8 by manipulation of handle 25, upon release of the means for locking plate 15 in inoperative position.

As a specific example of operation, a 30 denier, 10 filament yarn formed from polycaprolactam was twisted 4000 turns per meter at a speed of 40 meters per minute. The spindle 3, having a diameter of 4.5 mm., was driven at a velocity of 160,000 r.p.m. from a belt 8 travelling at a linear speed of 38 meters per second. The discs 11, including rims 10, had a diameter of 40 mm. and, therefore, rotated at approximately only one-ninth the speed of the spindle 3. A tube having a length of 35 cm. and a temperature of l60-170 C. was used as a heater, and the yarn was cooled, prior to passage through the false twisting device, by means of a tube having an inner diameter of 0.6 mm. and a length of 12 cm. which was kept at a temperature of 15 C. by a continuous supply of running water. With the device operating in the fore going manner, a very good twisting effect was obtained at commercially acceptable operating speeds. The elastic rims of the discs did not show any appreciable wear after weeks of operation.

It is pointed out further that the collar shape is not necessarily limited to frusto-conical, as shown, but may be cylindrical.

While various modifications and alternatives have been discussed hereinabove for purpose of description and explanation, it is to be understood that the scope of this invention is limited only to the extent defined in the following claims.

What is claimed is:

1. A device for twisting yarn, comprising, in combination with a plurality of discs rotatable about spaced fixed axes and forming therebetween a throat, a tubular twisting spindle, adapted for rotation, received within said throat, drive means for imparting rotation to said tubular twisting spindle and for urging the same into the throat of said discs, and means including an air bearing for preventing movement of said tubular twisting spindle in the direction of yarn advance, said air bearing comprising an annular collar positioned on said tubular twisting spindle and a relatively fixed annular air chamber cooperating with said collar and having a source of supply of compressed air connected thereto.

2. A device for twisting yarn, comprising, in combination with a plurality of discs rotatable about spaced fixed axes and forming therebetween a throat, a tubular twisting spindle, adapted for rotation, received within said throat, drive means for imparting rotation to said tubular twisting spindle and for urging the same into the throat of said discs, and means including a collar fixed to said tubular twisting spindle and a relatively fixed air chamber, having a source of supply of compressed air connected thereto, cooperating with said collar for preventing movement of said tubular twisting spindle in the direction of yarn advance.

3. A device for twisting yarn in accordance with claim 2 wherein the air chamber is annular in form and surrounds the tubular twisting spindle below the collar.

4. A device for twisting yarn in accordance with claim 3 wherein the lower end of the tubular twisting spindle is provided with a yarn encircling body and wherein the tubular twisting spindle is accurately cylindrical over the whole length between the collar and the yarn encircling body, the construction and arrangement being such that the tubular twisting spindle may be inserted within the annulus of the air chamber from above.

5. A device for twisting yarn in accordance with claim 3 wherein the annular air chamber is provided with a nozzle having openings therein for directing air onto the bottom surface of the collar.

6. A device for twisting yarn, comprising, in combination with a plurality of discs rotatable about spaced fixed axes and forming therebetween a throat, a tubular twisting spindle, adapted for rotation, received within said throat, drive means for imparting rotation to said tubular twisting spindle and for urging the same into the throat of said discs, means including a collar fixed to the upper end of said tubular twisting spindle and an air chamber, having a source of supply of compressed air connected thereto, cooperating with said collar for preventing movement of said tubular twisting spindle in the direction of yarn advance, said air chamber being disposed around said tubular twisting spindle and being relatively stationary with respect to said tubular twisting spindle, and means for adjusting the position of said air chamber relative to the throat formed by said discs.

7. A device for twisting yarn, comprising, in combination with a plurality of discs rotatable about spaced fixed axes and forming therebetween a throat, a tubular twisting spindle, adapted for rotation, received within said throat, drive means for imparting rotation to said tubular twisting spindle and for urging the same into the throat of said discs, means including a collar fixed to the upper end of said tubular twisting spindle and an air chamber, having a source of supply of compressed air connected thereto, cooperating with said collar for preventing movement of said tubular twisting spindle in the direction of yarn advance, means for supporting said air chamber including a vertical column and a tube connecting said column and said air chamber, and means carried by said column for holding said tube in position, said latter means also functioning to adjust the position of said air chamber relative to the throat formed by said discs.

8. A device for twisting yarn, comprising, in combination with a plurality of discs rotatable about spaced fixed axes and forming therebetween a throat, a tubular twisting spindle, adapted for rotation, received within said throat, drive means for imparting rotation to said tubular twisting spindle and for urging the same into the throat of said discs, means including a collar fixed to the upper end of said tubular twisting spindle and an annular air chamber, having a source of supply of compressed air connected thereto, cooperating with said collar for preventing movement of said tubular twisting spindle in the direction of yarn advance, said air chamber being disposed coaxially about said tubular twisting spindle, and means for adjusting the position of said air chamber relative to the throat formed by said discs.

9. A device for twisting yarn in accordance with claim 8 wherein the annular air chamber is provided with a nozzle having openings therein for directing air onto the bottom surface of the collar.

10. A device for twisting yarn, comprising, in combination with a plurality of discs rotatable about spaced fixed axes and forming therebetween a throat, a tubular twisting spindle, adapted for rotation, received within said throat, drive means for imparting rotation to said tubular twisting spindle and for urging the same into the throat of said discs, means including a collar fixed to the upper end of said tubular twisting spindle and a relatively stationary annular air chamber, having a source of supply of compressed air connected thereto, cooperating with said collar for preventing movement of said tubular twisting spindle in the direction of yarn advance, said air chamber being disposed coaxially around and spaced from said tubular twisting spindle, means for supporting said air chamber including a vertical column and a tube connecting said column and said air chamber, and means carried by said column for holding said tube in position, said latter means also functioning to adjust the position of said air chamber relative to the throat formed by said discs.

11. A device for twisting yarn in accordance with claim 10 wherein the annular air chamber is provided with a nozzle having openings therein for directing air onto the bottom surface of the collar.

References Cited in the file of this patent UNITED STATES PATENTS Kunzle Apr. 30, 1957 Keeler et al Sept. 30, 1958 Schrenk et al. Oct. 14, 1958 Boillat et al Dec. 9, 1958 Ubbelohde Dec. 9, 1958 Arthur et al. May 17, 1960 Ubbelohde July 11, 1961 

1. A DEVICE FOR TWISTING YARN, COMPRISING, IN COMBINATION WITH A PLURALITY OF DISCS ROTATABLE ABOUT SPACED FIXED AXES AND FORMING THEREBETWEEN A THROAT, A TUBULAR TWISTING SPINDLE, ADAPTED FOR ROTATION, RECEIVED WITHIN SAID THROAT, DRIVE MEANS FOR IMPARTING ROTATION TO SAID TUBULAR TWISTING SPINDLE AND FOR URGING THE SAME INTO THE THROAT OF SAID DISCS, AND MEANS INCLUDING AN AIR BEARING FOR PREVENTING MOVEMENT OF SAID TUBULAR TWISTING SPINDLE IN THE DIRECTION OF YARN ADVANCE, SAID AIR BEARING COMPRISING AN ANNULAR COLLAR POSITIONED ON SAID TUBULAR TWISTING SPINDLE AND A RELATIVELY FIXED ANNULAR AIR CHAMBER COOPERATING WITH SAID COLLAR AND HAVING A SOURCE OF SUPPLY OF COMPRESSED AIR CONNECTED THERETO. 